Here are two videos of head lice crawling on and off the hair.
This video uses high magnification to show you how clumsily the louse moves when it doesn't have strands of hair to crawl along. You can clearly see the human blood in the center of its body. Note the six claws. Lice use their claws to move from the hair of one person's head to another during head-to-head contact, the most common form of head-lice transmission.
I took this video with my phone's camera. You can't see the details of the louse much, but it does give you a better sense of what you would see with your naked eyes. Notice how quickly the louse crawls along a single strand of hair.